Probing macrophage cell nucleotide sensing and calcium signaling through computation

虽然在恢复是一个自然的免疫系统反应，开始愈合过程，慢性在恢复- 信息与许多人类疾病有关，包括癌症、心脏功能障碍和败血症。的一个关键要素 在炎症反应中是巨噬细胞，一种消除病原体或垂死组织的白色血细胞。一个 内源性"危险信号"，三磷酸腺苷（ATP），刺激炎症通路中的Ca依赖性， 巨噬细胞虽然以前的研究在理解动画方面取得了很大的进步，但我的实验室试图 通过多尺度计算模型揭示ATP在炎症反应中驱动巨噬细胞的作用 我们发展。利用巨噬细胞炎症反应的新模型，我们的实验室可以预测蛋白质和细胞 行为的综合，生理系统，以更好地了解免疫系统。 目前ATP触发的巨噬细胞凋亡的范例是核苷酸的上调， 感知P2X通道在炎症反应中敏感，包括细胞因子和活性氧（ROS） release.然而，这一范式并不能解释几个观察结果。一，虽然P2X表达是 在炎性巨噬细胞中增加，这些受体也支持静息状态下的吞噬和迁移。 巨噬细胞这些过程是如何被P2X亚型（如P2X4和P2X7）选择性地控制的还没有解决。 第二，在炎症巨噬细胞中，许多感知Ca的蛋白质都具有翻译后修饰（PTM）， 然而，人们对PTM如何影响它们控制的免疫途径知之甚少。三、ATP的释放和降解 通过pannexins和外核苷酸酶控制激活P2X的ATP，但很少有研究评估它们的耦合。 我们的实验室具有独特的优势，可以通过探索这些观察结果背后的机制来扩展这一范式 以及P2X-、ATP-和Ca-驱动的再结晶中的大部分未研究的耦合。我们的实验室和组装的协作室- 演讲者将通过计算建模和实验方法研究整体假设：P2X 巨噬细胞中的通道通过ATP诱导的ATP释放（自分泌）帮助成核慢性炎症 选择性启动钙依赖性促炎信号通路的机制。这一假设 源于我们在最初的ESI MIRA奖项调查中出现的问题：1.增加 P2X4和P2X7表达及其在巨噬细胞中诱导的Ca信号延长了促炎性细胞因子的表达。 释放细胞因子和ROS？2.在钙敏感钙调素（CaM）中，像ROS氧化这样的PTM是否会减弱其 促炎信号通路的激活？3.（自分泌）ATP诱导的巨噬细胞ATP释放 延长促炎性细胞内Ca？ 我们通过计算了解巨噬细胞生理学的长期目标将加速实现 拟议的调查。这一赠款期的主要预期成果包括新机制， 用于由P2X受体介导的自分泌、ATP驱动的炎症反应的模拟工具。由于所有 真核细胞使用钙，从建模巨噬细胞的见解将有广泛的影响超越免疫功能。

While inflammation is a natural immune system response that begins the healing process, chronic inflam- mation is tied to many human diseases including cancer, cardiac dysfunction, and sepsis. A key element of inflammatory responses are macrophages, a white blood cell that eliminates pathogens or dying tissues. An endogenous 'danger signal', adenosine triphosphate (ATP), stimulates Ca-dependent inflammatory pathways in macrophages. While previous research has made great strides in understanding inflammation, my lab seeks to uncover roles of ATP in driving macrophage inflammatory responses through multi-scale computational models we develop. With new models of inflammatory responses in macrophages, our lab can predict protein and cell behavior in integrated, physiological systems to better understand the immune system. The current paradigm for ATP-triggered inflammation in macrophages is that upregulation of nucleotide- sensing P2X channels sensitizes inflammatory responses, including cytokine and reactive oxygen species (ROS) release. However, this paradigm does not account for several observations. One, while P2X expression is increased in inflammatory macrophages, these receptors also support phagocytosis and migration in resting macrophages. How these processes are selectively controlled by P2X subtypes like P2X4 and P2X7 is unresolved. Two, inflammatory macrophages harbor post-translational modifications (PTMs) of many proteins that sense Ca, yet little is known about how PTMs impact immune pathways they control. Three, release and degradation of ATP by pannexins and ectonucleotidases control ATP that activates P2X, yet few studies have evaluated their coupling. Our lab is uniquely positioned to extend this paradigm by probing mechanisms underlying these observations and the largely unstudied coupling of P2X-, ATP-, and Ca-driven inflammation. Our lab and assembled collab- orators will investigate the overall hypothesis via computational modeling and experimental approaches: P2X channels in macrophages help nucleate chronic inflammation via ATP-induced ATP release (autocrinic) mechanisms that selectively prime Ca-dependent, pro-inflammatory signaling pathways. This hypothesis stems from questions that emerged from our investigations during the initial ESI MIRA award: 1. Does increased P2X4 and P2X7 expression and the resulting Ca signals they induce in macrophages prolong pro-inflammatory release of cytokines and ROS? 2. Do PTMs like ROS oxidation in the Ca-sensor calmodulin (CaM) attenuate its activation of pro-inflammatory signaling pathways? 3. Do (autocrinic) ATP-induced, ATP release in macrophages prolong pro-inflammatory increases in intracellular Ca? Our long-term goal to understand macrophage physiology through computation will be accelerated by the proposed investigations. Key expected outcomes from this grant period include new mechanisms and simulation tools for autocrinic, ATP-driven inflammatory responses mediated by P2X receptors. Since all Eukaryotic cells use Ca, insights from modeling macrophages will have broad impacts beyond immune function.